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[ howling wind ]

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Walt: We just returned from the GPM Cold Season

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Precipitation Experiment held in Ontario, Canada.

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And it was a very successful experiment. We collected the bulk of the

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data that we went up there to get, and I think that everybody is very happy with the dataset.

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I would say that it did not snow across the norther tier of the United

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States and Southern Canada as much as we had hoped it would this year, but surprisingly

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enough, even given the relative lack of snow that we had,

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we got all the events that we basically wanted.

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One of the objectives for this field campaign was to

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test the range of snowfall intensities

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that occur. And the idea being there that we would be able to

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sort of find where it is in that spectrum of events that we would actually be able to

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detect falling snow from space with the GPM

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Core satellite.

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[ jet engine ]

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Through the duration of the campaign we went the full

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six weeks using all the aircraft hours that were available to us on the DC-8.

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We flew about 14 missions, for a total about 75 flight hours

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I sort of assumed we would show up and basically burn out our flight

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hours in a very short time up there in frequent heavy snowfall

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events, and what actually transpired is that we ended up using the entire

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duration of the field campaign to get our datasets because the snow events

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were sort of spaced fairly regularly and

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were not that heavy and we kept wanting to get the heavier event, and it took a while

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to get that.
Steve: As you can see it's snowing pretty good

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this morning at the CARE site. Pretty nice large aggregates.

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It's exactly what we're looking for and it just keeps coming down.

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Walt: So we've completed the GCPEx experiment in terms of being

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on the ground and collecting the data. Now a phenomenal effort actually goes

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into quality controlling all of the data we collected. That is, to make sure that

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all of those datasets that we collected are usable,

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there's no bad data in the datasets, and that has to be done for

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a huge number of ground instruments that were deployed, both radars

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direct measurements of snowfall using gauges, particle

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imaging systems, all of those data on the ground. And then you have to move to the aircraft

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data, which is also very complex because you've got several different probe types

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that were flying in the clouds, looking at different aspects of the precipitation

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and all of that data has to be quality controlled. And finally you have the

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satellite simulator, or the DC-8, that carried the radiometer, the

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COSMIR radiometer and the APR-2 radar.

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All of those data have to be--and we're talking gigabytes and terabytes--

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of data that has to be quality controlled. That will take on the order of six months to

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a year to accomplish. And that connection in between what I

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measured during this field campaign to what I think I'm going to see in space

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essentially encompasses the development process of

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making an algorithm to retrieve the snowfall from space.

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[ rain ]

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[ rain ]

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[ rain dripping ]

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